- Impaired cardiac function including any one of the following: complete left bundle branch block or use of a permanent cardiac pacemaker, congenital long QT syndrome, presence of ventricular tachyarrhythmias, clinically significant resting bradycardia (< 50 beats per minute), QT interval corrected by Fridericia's formula (QTcF) > 450 msec on screening electrocardiogram (ECG), or right bundle branch block + left anterior hemiblock (bifascicular block)